Reversible tube bender with side angle indicator



Feb. 24, 1948. T. v. PEARSON ETAL 2,436,776

' REVERSIBLE TUBE BENDER WITH SID'E ANGLE INDICATOR Filed March 1'7,1944 I5 Sheets-Sheet 1 Hands 1" Pea/50x1 Mayne/id Zafiooa Feb. 24, 1948.T. v. P-EARSON ETAL REVERSIBLE TUBE BENDER WITH SIDE ANGLE INDICATORFiled March 17, 1944 3 Sheets-Sheet 2 1 n eh fig??? Mayne/d 4460007/70/1105 [4 farzs on I l f wh 8 w% ww w .w\ i w L. Y O HHHI MHP HIHUHHH C on A a .w

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' 1943- T. v. PEARSON ET'AL REVERSIBLE TUBE BENDER WITH SIDE ANGLEINDICATOR I 3 Sheets-Sheet 3 Filed March 17, 1944 1 7/7omas V; Pea/ sonMayne ra la flood I-IKH Patented Feb. 24, 1948 REVERSIBLE TUBE BENDERWITH SIDE ANGLE INDICATOR Thomas V. Pearson and Maynerd Lahood, Akron,Ohio, assignors to Goodyear-Aircraft Corporation, Akron, Ohio, acorporation of Delaware Application March 17, 1944, Serial No. 526,87811 Claims. (01. 153-40) This invention relates to the improvement ofapparatus for bending tubes, and, in particular, to tube bendersoperated by hand. some features of this improvement, however, are alsoapplicable to power-driven tube benders.

Tube-bending apparatus of previous construction was not adapted to beoperated at high eificiency in output, nor was it very easy to produceexact duplicates of tubes formed.

It is the general object of this invention to avoid and overcome theforegoing'and other dif- Another object of this invention is theprovision of apparatus embodying quick change and.

fixation of the operating arm and the bending block arm from theposition of making righthanded bends to that of making left-handedbends.

Another object of this invention is the avoidance of a slidable tubeguide moving together with the tube to be bent.

A further object of this invention is the inclusion of means for theinstant determination of the side angle between bends of a tube, thatis, the angle between the planes of adjacent bends.

The aforesaid objects of the invention, and other objects which willbecome apparent as the description proceeds, are achieved by providing,first, an index segment adapted for inserting a stop for determining thedesired bending angle and to insure exact duplication of parts; second,a set of guiding rolls on the stationary vise support instead of asliding part moving with the tube to be bent; third, a quicklyreleasable lock between the operating or bending arm and thebendingblock lever for changing the operating lever to the other side for thepurpose of making reversed bends; and, iourth',-a diametrical loosenection with the tube bender; Fig. 5 is a front view in the directionV--V of Fig. 4; Fig. 6 is a top view, partly in section, of Fig. 5; andFig. 7 is a fragmentary front view of the side angle indicator.

Although the principles of this invention are not restricted to thespecific construction shown in the drawings, it will be described asillustrated;

With specific reference to the form illustrated in the drawing, thenumeral l0 indicates the base as a whole of ahand-operated bendingmachine of known construction, which includes U- shaped supports 12 andI4 extending from the center. outwardly in opposite directions. a centerpin l6, fixed in the base 10, is swingable a lever I8, to-the end ofwhich is pivotally attached the fo'rked end of the bending lever 20,indicated as a whole, by a pin 22 screwed into the bottom side of thefork 2 4, which is provided on the top side with straight flanks 26,instead of having the usual rounded end like the bottom side. The hub ofthe lever [B flush with the top of the fork 24 is cut off sufiicientlyat one side to provide space for an easily removable key 28 of U-shape,which looks the operating or bending lever 20 in its position relativeto the lever is. However, when the key 28 is removed the empty spaceleft permits the lever 20, in spite of its straight flanks 26 of theupper fork end, to be swung about the pin 22 into a position oppositetherefrom in which it is again locked together with the lever I8 to bethen operated from this side for making bends in reversed direction.

On the pins l6 and 22, extending over the hub of the lever l8 and fork24, respectively, is removably mounted the bending block 30, which,

' because of the key 28, can beoperated by the bending lever 20. Thebending lever 20 includes a slidable support 32 which holds, by springmeans 34, in loose connection, a tube vise jaw 36. This jaw is pressedagainst the straight portion of the bending block, for tightly grippingthe tube, by

means of a spindle 38 provided with a handle 0.

The spindle 38 turns in a half nut 42 fastened to the near end of thebending lever, thus permitting the spindle to be lifted out from'thehalf nut for rapid operation of the clamp.

Cooperating with the bending block is a second vise 50, indicated as awhole, which consists of a guide piece 52 adjustably mounted and held inplace we removable pin 54 either on the support 12 or [4,- depending onwhether a. rightor left-handed bend is to be made, and of a slidableAbout support 50 which carries two tube guide rolls 58 revolvable onpins 60 inserted in the support 56 and cooperating with the "bendingblock 30. These rolls can be engaged with and disengaged from thebending block by a spindle 62 turning in a half nut 42' and permittingit to be lifted out from the half nut. The guiding rolls 58 have theadvantage over previous constructions that during the bending processthey are stationary, unlike the guide piece which used .to move togetherwith the advancing tube and which had to be put back to its originalposition at each bending operation.

To simplify quick determination of the cor- 'rect bending angle of thetube without loss of time, the segment 66, fastened 'to the base I bybrackets 61 is provided with holes 68 marking the bending angles of thetube. Five holes, substantially radially aligned, are positioned at eachincrement of degrees on the segment 66. A pin I0, adapted to engage withthe side of a lever 20, is inserted as a bending lever stop in the hole80 indicating the angle the tube is to be bent. This pin 10, bestillustrated in Figure 2, is shown in Figure 1 in zero position fromwhere it is moved to a hole 08 whichever corresponds to the desiredbending angle as indicated, for instance, by the position of the bendinglever at 21 degrees in dotted lines. The movement of the bending leverfrom one hole to the next one corresponds to one degree bending angle.This arrangement will admit of fast handling with no loss of time forwatching the bend angle indicator at each separate bending process.

For quickly making accurate side angle tube bends, the side angleindicator 86 of conventional construction, including the dial 81, usedin combination with the tube bender, both of which are mounted on atable 88, is provided at the front end of its rotatable hollow indicatorshaft 90 with a knife-like edge 92. This'knife edge fits into slots of ashouldered bushing 94, to which it is fastened and which is insertedinto the bore of the shaft 90. The knife edge 92 also is held,

by slots 96 in the front end of the shaft against turning of the bushing94 in the bore, and a set screw 98 secures the bushing in its location.To readily match the notch I00, sawed into the end of the tube T, withthe knife edge 92, an angularly-shaped guide I02 is attached to asupport I04, which is fastened to the vertically-adjustable dial frameI06. A set screw I08 holds the dial at the angle at which the tube is tobe bent relative to the position of slot in the tube. cases the tubes ofsmaller size can be bent without a mandrel. However, in cases where amandrel is required, the knife blade 92 will be cut out at the lines IIOto permit a passage for the mandrel. I

From the foregoing description it should be clear that the operation ofthe improved tube bender by the various features described is very muchsimplified, as compared to previous constructions. For reversing thebending operation, after removing the bending block 30, the key 28,which, of course, can be replaced by other similar means, can be readilyremoved for swinging the bending lever'in opposite directions, which inthis. latter position is secured again with subsequent insertionof thebending block upside down in opposite position. In addition the vise 50,including the elements 52, 56 and other associated parts secured by thepin 54 to the support I2 is removed and mounted on the support I4opposite thereof. This change, of course, re-

In most quires that also the dial assembly 86 is moved laterally to aposition symmetrical to that of the blank, as shown in Figure 1. Thisarrangement avoids the need of using a bevel gear drive, which is ratherexpensive and unnecessary for smaller size tubes, such as occur to agreat extent, especially in the aircraft industry and in similarlyrelated art.

The index segment 66 used instead of the conventiorial dial for readingthe bending angle, has the great advantage that by inserting the pin 10in one of the holes determining the desired bend-' ing angle,differences in the shape of tubes to be duplicated are entirelyexcluded, and the time for reading the dial for each bend is saved.

A further saving of time is achieved by the arrangement of stationary,rotatable tube guide rolls 58 keeping the tube in proper alignmentduring bending and saving the much more expensive slldable tube guidewhich also at times interferes with unobstructed production.

For tubes having multiple bends, the notch and knife edge indexingmethod is much more economical in bending a batch of tubes by firstmaking one and the same bend on all tubes, so that only one setting ofthe tube bender is required for that particular bend and again only onesetting for every other different bend, instead of completing all bendson each separate tube. The latter process was necessary when clampingthe tube in the side angle indicator in order to obtain the correct sideangles between the bends, because, after once having removed the tubefrom the side angle indicator after the first bend, it was cumbersome tomake adjustments for finding the side angle for the next bend. Inaddition, under such circumstances, adjustments on the tube bender hadto be made after each separate bend. All of these diificulties areremoved by providing each tube at one end with a diametrical saw cut I00 of low depth which, held against the knife edge 92, being, forinstance, in horizontal position and clamped against the bending block,makes the first bend of the tube run in the direction of the slot I00.This same process is repeated for each tube. Now the side angle is seton the side angle indicator, the tube again indexed by the knife edge,and bent in the usual way, thus exactly duplicating the side angle foreach tube. By this method of indexing and bending, the time for bendinga batch of tubes, can be considerably shortened as compared with that ofthe old method, and, at the same time, a more uniform product will beobtained. It should be' mentioned here that this last feature is notrestricted to hand-operated tube benders, but may be equally wellapplied to power-driven tube benders.

From the foregoing description, it will be obvious that the improvementspresented in this case are a considerable step forward in thetubebending art, since the cost and time of production is cut to aminimum.-

While, in accordance with the patent statutes only one embodiment of theinvention has been illustrated and described in detail, it is to beparticularly understood that the invention is not limited thereto orthereby, but that the inventive scope is defined in the claims.

We claim:

1. The combination, with a tube bender, in cluding a base, of a centerpivot in said base, a bending block revolvable about said pivot, meansfor clamping and shaping a. tube to be bent against said bending block,a side angle indicator spaced from said tube bender being provided witha centrally positioned knife edge for loosely engaging adiametricallyslottedend of said tube for. the purpose of indexing theside angle between bends of the tube.

.2. The combination with a tube bender of a side angleindicator having arotatable dial, a shaft fixed to and supporting this dial, and a knifeedge diametrical to and attached to thefront of said shaft for looselyengaging a diametrically slotted end of a tube to be bent for thepurpose of indexing the side angle between bends of the tube.

3. The combination with a tube-bender of a side angle indicator having arotatable dial, a shaft fixed to and supporting this dial, and a knifeedge securely attached in diametrical po- 'sition to the front face ofsaid shaft for loosely engaging'a diametrically slotted end of atube tobe bent for the purpose of indexing the side angle a slot cut into oneend of the tube to be bent .for indexing the side angle between aplurality of bends of said tube.-

5. The combination with side angle indicator having a rotatable dial, a

hollow shaft fixed to and supporting said dial, a

tubular holder inserted in the front end of said shaft and securedthereto against relative movement, and a knife edge index diametricallyattached to said holder, said knife edge being made in two parts spacedapart in the center for passage of a tube mandrel and fitting into adiametrical slot cut into one end of the tube to be bent for indexingthe side angle between bends of the tube.

cluding a, base, of a center pivot in said base, a bending blockrevolvable about said pivot, a bending lever turning said bending blockabout a tube bender, of a' assume the tube to be bent to the bendingblock, a fixed guide piece adjustable on said base, a second vise,includingflguiding rolls, slidable on said guide piece for guiding andholding the tube durin bending against the bending block at a pointsubstantially opposite its center, a side angle indicator, spaced fromthe tube bender and having a rotatable hollow shaft'having a dialdivided in degrees fixed thereto for indexing the side angle between twotube bends, and a knife edge, diametrically attached to one end face ofthe shaft, adapted to be inserted in a correspondingly placed slot cutinto one end face of said tube.

8. The combination with a reversible tube bender, including a' base, ofa center pivot in said base, a short lever turnable about said pivot.

a bending lever adapted for bending a tube, a second pivot swingablyconnecting one end of said bending lever with the free end of said shortlever, means for releasably coupling said levers together into rigidrelationship with each other so that they can be swung as a unit aboutsaid center pivot, an index segment attached to said base concentric tothe center pivot and being provided with holes marking the degrees ofthe bend angle, and a removable stop insertable in one of these holesfor arresting said bending lever.

9. The combination with a reversible tube bender, including a base, of acenter pivot in said base, a short .lever turnable about said pivot, abending lever adapted for bending a tube, a second pivot swingablyconnecting one end of said bending lever with the free end of said shortlever,

8. The combination with a tube bender, in-

said pivot, an index segment provided with holes determining the bendingangle, a removable pin put in one of said holes for stopping the bendinglever from further movement, a side angle indicator spaced from the tubebender, having a rotatable dial, a shaft supporting the dial andindexing means diametrical to and attached to the front of said shaftfor loosely engaging a diame rically slotted end of a tube to be bentfor the purpose of indexing the side angle between bends of the tube.

7.1The combination with a reversible tube bender, including a base, of acenter pivot in said base, a lever turnable about said pivot, a

bending lever adapted for bending a tube, a second pivot for swingablyconnecting one end of said bending lever with the free end of said firstlever, means for releasably coupling said levers together into rigidrelationship in two different positions, so that they can be swung as aunit about said center pivot for making right and left turn bends,respectively, an index segment concentric to-said center pivot andprovided with holes for marking the degrees of the bendin angle, a pinto be inserted into one of'said holes as a stop for. said bending lever,a reversible bending block held in position by said two pivots, a viseslidable on said bending. lever for clamping and means releasablycoupling said levers together into a rigid relationship in either one oftwo opposite positions so that they can be swun as a unit about saidcenter pivot for making right and left turn bends, respectively.

10. The combination with a reversible tube bender, including a base, ofa center pivot in said base, a short lever turning about said pivot, abending lever adapted for bending a tube, a second pivot swingablyconnecting one end of said bending lever with the free end of said shortlever, and a key inserted between straight faces of and releasablycoupling said levers together into a rigid relationship with each otherin two oppo-' site positions so that they can be swung as a unit aboutsaid center pivot for making right and left turn bends, respectively.

11. The combination with a reversible tube bender, including a basehaving vise supports extending in opposite directions, of a center pivotin said base, a short lever turnable about said pivot, a bending lever,a second pivot swingably connecting one end of said bending lever withthe free end of said short lever, means releasably coupling togethersaid levers into rigid relation in either one of two opposite positionsso that they can be swung as a unit about said center pivot for makingright and left turn bends, respectively, a reversiblebending blockhaving a contour partly curved and partly straight and being held inposition by said two pivots, a vise combined with said bending lever toclamp a tubing to be bent against the bending block, a second vise,including revolvable rolls, slidable and adapted to be fixed in variouspositions on said supports for guiding and holding the tube against thebending block at a point of same substantially where the straight partturns into The following refere11ces are 0! record In the arm-mucus crmnfile of this patent: I

UNITED STATES PATENTS Number Name Date' Hooker Dec, 14, 1880 Neuert Dec.19, 1905 Nflmber

